The present invention provides an improved process and apparatus for preparing dissipations of liquid-dissipatable polymers. Such polymers are well known in the art and include cellulosic polymers, acrylic polymers, polyesters, etc. While it is known that such polymers as these form dissipations in appropriate liquids, previously known processes for preparing such dissipations have proved inadequate.
For example, a commonly employed dissipation technique involves extruding a polymer as molten strands into an agitated open tank of a desired solvent. This system must be highly agitated in order to achieve the desired dissipation; however, the extrusion rate and mixer speed must be critically controlled in order to avoid balling of the polymer on the agitator. Furthermore, such prior art processes impose limitations upon the compositional ranges of dissipations which can be prepared thereby.
In contrast, the present invention provides a process and apparatus whereby dissipations can be prepared rapidly with a minimum of capital investment. In the case of polymers, there is no significant loss in polymer inherent viscosity (I.V.) during operation of the process. Furthermore, the composition of the polymer dissipation can be varied from very high to very low concentrations of polymer in the dissipating liquid. Also, the particle size distribution is improved. As used herein, the term "dissipate" and variations thereof is intended to mean both "dissolve" and "disperse" and combinations thereof.
The present invention provides a process and apparatus for preparing dissipations of liquid-dissipatable polymers. The process can, in a continuous manner, prepare stable, excellent dissipations by contacting the polymer and dissipating liquid by mixing them under conditions and for a time sufficient to dissipate the material in the liquid.